Stoking mechanism



Oct. 14, 1941. w. T. HANNA STOKING MECHANISM Fil ed Jan.

INVENTOR.

m'lliam' 7: Hanna ATTO EYS Patented Oct. 14, 1941 STATES PTENT OFFICE STOK-ING MECHANISM William Thompson Hanna, Cincinnati, Ohio v v H Application January 2'7, 1938, Serial No. 187,152 7 l 10 Claims.

The present invention relates to an improvement in locomotive stokers, wherein coal of heterogeneous particle size is automatically moved from a tender past a crusher to the locomotive firebox. One object of the invention is to provide improved mechanism relatively inexpensive to manufacture for controlling and/or conditioning the fuel flowing to fuel distributing mechanism. Other advantages and beneficial features of the improved apparatus will be apparent to those skilled in the art.

One embodiment of the invention in a form designed for use with locomotive stokers is illustrated in the drawing accompanying the present specification and in which:

Figure 1 is a central longitudinal vertical section of a portion of a stoking device applied to a locomotive firebox;

Figure 2 is an oblique section on the line 2-2 of Figure 1;

Figure 3 is a horizontal section on the line 33 of Figure 1; and

Figure 4 is a section on the line '44 of Figure 2.

As shown in the drawing, a cylindrical coal feeding conduit I located above the deck D of a locomotive is provided with a screw conveyor having a hub 2 journaled at 3 and driven by a shaft 4 through a suitable coupling, the yoke of which is shown at 5. The shaft 4 may be driven through the coupling by suitable known means. 'Coal is fed to conduit I from an elevating conduit 6 which in turn is connected with a transfer conveyor (not shown). The transfer conduit conveys the fuel forwardly from a tender hopper (not shown) duit I through a delivery port I.

The delivery end of conduit I opens into a chamber Ia wherein coal mass fed thereto from conduit I is brought to a suitable loose and mobile condition and in which chamber the passage of the fuel to distributing apparatus generally indicated at I is controlled. The chamber la is part of a housing generally indicated at I0 I which encircles and encloses the firing opening II in the back head I2 of the locomotive. The housing Ill! has a hand-firing opening I02 normally closed by a fire door, not shown. The chamber is located in the lower portion of the housing and comprises an upwardly, forwardly sloping bottom wall I4 having a central flat fuel supporting surface I6 and side triangularly shaped fuel supporting surfaces I! and I8 which drop away from the surface I6 as shown in Figures 1 and 2. The surface I6 narrows to- Elevating conduit 5 enters the conmechanism I 00.

I8 widen toward the upper ends. Surface I 6 terminates in a horizontal ledge I9, but surfaces I1 and I8 terminate in edges Ila and 1811, respectively.

The sides of the chamber are formed by vertical diverging walls I5 and I5a which extend into the side walls of the housing I01. The top wall of the chamber is substantially horizontal and is not as long as the bottom wall I4 so that the two walls I3 and I4 and the side walls 15 and l5a form a chamber which widens toward its delivery opening and which has a portion thereof restricted by the top wall I3 for a portion thereof.

Referring to Figure 1, located immediately in front of the ledge I9 is a combined blast chamber and fuel screening device generally indicated at 30 and which is part of the fuel distributing This device is shown and described in greater detail in my United States Patent No. 2,090,628, and comprises generally a plurality of diverging fingers 30a having diverging openings 30b therebetween and fuel supporting surfaces 380 on the top thereof which slope downwardly and forwardly. A blast of steam is emitted from the end of each finger supplied through a suitable source as described in the said 'dition runs down over the fingers and is screened so that the larger particles of fuel ride over the top of the fingers and are carried off by the jets from the fingers themselves, whereas the finer fuel drops between the fingers and is carried on by the sheet jet which generally is emitted with less force than the jets from the fingers.

Ledge I9 is effectively continued by the top surfaces 2Ila and 26a of adjustable gates or plates 29 and 26 pivotally mounted in the forward end of bottom wall I4 to move between the distributing mechanism I00 and the edges Na and IBa. The plates are respectively mounted on studs 2I and 21, Figure 4, projecting from the underside of wall I4. The longitudinal axes of the studs are inclined in such manner that said gates 20 and 26 may be swung up and down, for example, be-

tween the extreme positions more clearly shown wards its uppermost end and the surfaces I1 and in Figure '2 where the uppermost position of gate 20 is indicated in dotted lines. An arm 22, Figures 2 and 3, provided with a hand hold extends laterally from the outer edge of each gate. It will be obvious that by proper manipulation of said arm 22, gate 20 may be swung between the retracted position, indicated in full lines, and the extended position, indicated in dotted lines in gure 2.

As shown more clearly in Figures 2 and 3, the gates with their surfaces 20a and 26a form an extension of the ledge I9 and by adjusting these gates the slope of the ends of this effective ledge toward its center may be raised or lowered. Thus when the gates are in their raised (dotted line) position, the coal discharged over the ledge is concentrated in the central portion thereof, but when they are lowered to the full line position, the coal delivery is spread out more over the ledge. This arrangement enables the operator to vary the amount of coal delivered to the different areas or zones of the firebox at will while maintaining a substantially constant rate of coal feed to the fire as a whole.

To obtain the most efficient operation of the distributing mechanism, the fuel reaching it, as above pointed out, should be loose so that the screening effect of the fingers is obtained. Also the flow of fuel to the distributing mechanism should be regulated and substantially uniform so that the fuel-handling capacity of the distributing mechanism is never exceeded.

To this end, the hub 2 carries a helical screw having a hubless conditioning forward vane portion 28 extending beyond the delivery end of the conveyor vane portion 29 and hub 2. The conveyor vane 29 is preferably of uniform diameter and pitch, whereas, the hubless vane portion 28 tapers toward its forward end and is of progressively diminishing pitch. As shown in the drawing, the taper of the hubless worm 28 conforms approximately to the converging angle of the bottom wall and the short top wall of th conditioning chamber, and to the converging edges of the bottom wall surface I6.

In operation, the coal is fed from the transfer conduit from below the locomotive cab deck up through the conduit 6 into the conduit I. There it is forced by the conveyor 29 forwardly through the chamber over the ledge I9, 20a and 26a to the distributing mechanism. The fuel coming in contact with the rotating hubless vane 28 with its decreasing pitch and taper, and so with its materially decreasing fuel handling capacity, is loosened, disrupted, or generally caused to move sideways and forwardly and to spread out. Thus it is caused to move over the ledge I9, 20a and 26a in a regulated stream in a condition thinner than the fuel emerging from the conduit 6. As above described, the direction of the main flow of fuel and/or the concentration of the stream of fuel, i. e., the depth of the stream, may be controlled by the gates 20 and 26, thus to concentrate the delivery .of the fuel where desired. But under no circumstances is the fiow of fuel stopped by the conditioning or gate mechanism. The short top wall I3 permits the fuel to boil up in the event that the supply is increased when the gates are in their uppermost positions so that the coal simply rises to a higher level in the conditioning chamber and flows over the gates and over the central ledge portion I9.

To concentrate delivery of the fuel in the central longitudinal zon of the firebox 'more than at the sides of the firebox, both gates are raised, as to their dotted line positions (as shown in Figure 2), thus forming a narrower but deeper discharge passageway. For the distribution of fuel more centrally over a wider central area, the gates are retracted to lower th side portions 20a and 26a of the ledge. If a greater supply of fuel is needed at one side of the firebox than at the other, one gate will be raised and the other lowered.

As various embodiments might be made in the construction herein described, all without departing from the scope of the invention, it is to be understood that all matter herein set forth or shown in the accompanying drawing is to be interpreted as illustrativ and not in a limiting sense.

I claim:

1. Stoker mechanism adapted to be mounted on the backhead of a locomotive firebox and comprising a cylindrical feed conduit, a conditioning chamber connected thereto and having lateral wall portions diverging and top and bottom wall portions converging to form at their outer edges a laterally extended and vertically restricted discharge opening, said bottom wall portion being formed to present interiorly a centrally disposed coal supporting surface and a laterally disposed coal supporting surface at each side thereof and inclined at an angle thereto, a gate mounted for swinging movement across the outer edge of each of said laterally disposed inclined coal supporting surfaces to adjustably define a passageway for coal to be discharged through said opening, means for actuating said gates, and a screw conveyor operatively mounted to rotate in said conduit and having a helical vane of which a conveyor portion extends lengthwise through said conduit and a coal conditioning portion extends into said passageway.

2. Stoker mechanism adapted to be mounted on the backhead of a locomotive firebox and comprising a cylindrical feed conduit, a conditioning chamber connected thereto and having lateral wall portions diverging and top and bottom wall portions converging to form at their outer edges a laterally extended and vertically restricted discharge opening, said bottom wall portion being formed to present interiorly a centrally disposed coal supporting surface and a laterally disposed coal supporting surface at each side thereof and inclined at an angle thereto, a gate mounted for swinging movement across the outer edge of each of said laterally disposed inclined coal supporting surfaces to adjustably define a passageway for 'coal to be discharged through said opening, means for actuating said gates, and a screw conveyer having a helical vane of which a uniformly pitched conveyer portion is mounted on a hub in said cylindrical conduit and a tapering conditioning portion of progressively diminishing pitch extends beyond said hub into said conditioning chamber and cooperates with a portion of the top thereof and with a portion of said centrally disposed coal supporting surface to condition coal for delivery through said discharge opening.

3. In a stoker, the combination with a locomotive, firebox having a fuel entrance, of a conduit for transferring fuel and delivering it to said entrance terminating in a fuel conditioning chamber adjacent said fuel entrance, a casing embracing said fuel entrance, said conditioning chamber being pairt of said casing said casing having a hand-firing opening above the conditioning chamber, said conditioning chamber being provided with a bottom wall sloping upwardly and forwardly and terminating at a ledge over which the fuel flows, side walls diverging forwardly, and a short top wall converging forwardly with respect to the bottom wall, and gate means forward of said conditioning chamber adapted effectively to form side extensions of said ledge, said gates being adjustable to vary the angles that said extension surfaces make with respect to said ledge.

4. In a locomotive stoker for feeding coal from a tender to the firing opening of a firebox, in combination, a conduit for conveying coal from the tender to the firing opening, said conduit terminating at its forward end in an expanded mouth portion extending forwardly and upwardly and connected to said firing opening, said mouth portion having a delivery ledge extending across said firing opening and over which coal fiows to said firebox; a screw conveyor in said conduit for moving the coal therethrough, and a tapered screw extending from the end of said screw conveyor and located in said mouth portion, said tapered screw having a shorter pitch than said screw conveyor to cause coal entering said mouth portion from the conduit to move sidewardly and forwardly to the full length of said delivery ledge, and means associated with said delivery ledge and pivoted in a plane parallel thereto for effectively giving the respective portions of said ledge on' either side of the center thereof angles of inclination with respect to the horizontal to cause the amount of coal flow over the said portions to decrease progressively away from the center thereof, said means being pivotable to adjust the said angles of inclination to regulate the amount of the said graduated decrease in concentration of coal flow.

5. In a locomotive stoker for delivering coal through a firing opening in the backhead of a locomotive firebox, the combination of, a conduit delivering coal to said opening and having a delivery ledge extending across said opening over which coal flows to said firebox, and adjustable gates associated with either side of said ledge, each gate being pivotable about an axis approximately perpendicular to the plane of said firing opening, adjustment of said gates serving to adjust the angle of the side portions of the ledges to adjust the flow of coal to the back corners of the firebox.

6. In a locomotive stoker for delivering coal through a firing opening in the backhead of a locomotive firebox, the combination of, a con-v duit delivering coal to said opening and having a delivery ledge extending across said opening over which coal flows to said firebox, and adjustable gates associated with either side of said ledge, each gate being pivotable about an axis generally located centrally of and slightly below said ledge, adjustment of said gates serving to adjust the angle of the side portions of the ledges to adjust the fiow of coal to the back corners of the-firebox.

7. In a stoker, the combination with a locomotive firebox having a coal entrance of, a conduit for transferring coal and delivering it to said entrance, said conduit terminating in a coal-conditioning chamber mounted adjacent said coal entrance, said chamber having a delivery opening comprising a ledge extending across said entrance and over which coal flows into said entrance, means associated with said chamber for causing the coal moving therethrough to spread therein and fiow over the sides of said ledge, said ledge having vertically adjustable side portions each of which is adjustable so as to position its ledge surface at varying angles to the horizontal and thus concentrate the coal flow at the center of said delivery opening or at either side thereof.

8. In a stoker, the combination with a locomotive firebox having a coal entrance of, a conduit for transferring coal and delivering it to said entrance, said conduit terminating in a coal-conditioning chamber mounted adjacent said coal entrance, said chamber having a delivery opening comprising a ledge extending across said entrance and over which coal flows into said entrance, the side walls of said chamber diverging and at least one of the top and bottom walls of said chamber being provided with inwardly projecting centrally located portions for causing the coal moving therethrough to spread therein and flow over the sides of said ledge, said ledge having vertically adjustable side portions each of which is adjustable so as to position its ledge surface at varying angles to the horizontal and thus concentrate the coal flow at the center of said delivery opening or at either side thereof.

9. In a locomotive stoker for delivering coal through a firing opening in the backhead of a locomotive firebox, the combination of a conduit delivering coal to said opening and having a delivery ledge extending across said opening over which the coal flows to said firebox, and means associated with said delivery ledge and pivoted in a plane parallel thereto for effectively giving the respective portions of said ledge on either side of the center thereof angles of inclination with respect to the horizontal to cause the amount of coal flow over the said portions to decrease progressively away from the center thereof, said means being adjustable to adjust the said angles of inclination to regulate the amount of the said graduated decrease in concentration of coal flow.

10. In a locomotive stoker for delivering coal through a firing opening in the baokhead of a locomotive firebox, the combination of a conduit for conveying fuel to said opening, said conduit WILLIAM THOMPSON HANNA. 

